Gluteus Maximus

Origin: Ilium post. to post. gluteal line; surface of sacrum and coccyx; sacrotuberous ligt.

Insertion: IT band and gluteal tuberosity.

Action: Chief extensor of the thigh (esp. from a flexed position); assists with ER of thigh and in from a seated position.

Innervation: Inferior gluteal n. (L5, S1, S2)

Blood Supply: Inferior gluteal a.

Gluteus Medius

Origin: Ext. surface of ilium between ant. and post. gluteal lines.

Insertion: Lat. surface of greater trochanter of femur.

Action: ABD and IR of thigh; Keep pelvis level when ipsilateral limb is weight-bearing. Advances opposite side (unsupported) side during its swing phase.

Innervation: Superior gluteal n. (L5, S1)

Blood: Superior gluteal and ascending branch of lat. femoral circumflex aa.

Gluteus Minimus

Origin: Ext. surface of ilium between ant. and inf. gluteal lines.

Insertion: Ant. surface , greater trochanter of femur.

Action: ABD and IR of thigh; keep pelvis level when ipsilaterl limb is weight-bearing. Advances opposite side during its swing phase.

Innervation: Superior gluteal n.

Blood: Superior gluteal and ascending branch of lat. femoral circumflex aa.

Tensor Fascia Lata

Origin: ASIS; ant. part of iliac crest.

Insertion: IT band

Action: ABD and IR of thigh; keeps pelvis level when ipsilateral limb is weight bearing. Advances opposite side during its swing phase.

Innervation: Superior gluteal n.

Blood: Sup. gluteal and ascending branch of lat. femoral circumflex aa.

Piriformis

Origin: Ant. surface of sacrum; sacrotuberous ligt.

Insertion: Sup. border of greater trochanter of femur.

Action: ER of extended thigh; ABD of flexed thigh; steadies femoral head.

Innervation: Ventral rami S1,S2

Blood: Superior and inferior gluteal aa.http://upload.wikimedia.org/wikipedia/commons/5/55/Posterior_Hip_Muscles_1.PNG

Superior Gemellus

Origin: Iscial spine.

Insertion: Trochanteric fossa of femur via tendon of obturator internus m.

Action: ER of extended thigh; ABD of flexed thigh; steadies femoral head.

Innervation: Nerve to obturator internus (L5, S1)

Blood: Inf. Gluteal and med. femoral circumflex aa.

Obturator Internus

Origin: Pelvic surface of obturator membrane and surrounding bones.

Insertion: Trochanteric fossa of femur.

Action: ER of extended thigh; ABD of flexed thigh; steadies femoral head.

Innervation: Nerve to obturator internus.

Blood: Pelvic part- Obturator a.

          Extrapelvic part- Med. femoral circumflex a.

Inferior Gemellus

Origin: Ischial tuberosity.

Insertion: Trochanteric fossa via tendon of obturator internus

Action: ER of extended thigh; ABD of flexed thigh; steadies femoral head

Innervation: Nerve to quadratus femoris (L5, S1)

Blood: Med. femoral circumflex a.

Quadratus Femoris

Origin: Lat. border of ischial tuberosity.

Insertion: Quadrate tubercle on intertrochanteric crest of femur and area inf. to it.

Action: ER of thigh; steadies femoral head.

Innervation: Nerve to Quadratus femoris (L5, S1).

Blood: Med. femoral circumflex a.